Hi @jillphoenixmayo Welcome to Arizona Shortly. Yes at least i see by a google search a couple of them within about 10 miles of the clinic. I personally live in Arizona, so I haven't had the pleasure of staying at any of them. But as for your question about parking for the day That I'm not sure what the policy is. There always seems to be room at the back area of a few of the parking lots. They had set-up a prescreening area during the height of the pandemic but have since taken it down so that freed up a lot of parking lot space. So maybe a call to the Numbers Colleen had a link too maybe a good Idea.
You may want to call those RV parks as soon as you can as we have entered our busy season. Usually, October is the start of when all our winter visitors start coming here from the northern area's. Here are some web pages to the ones I saw in a google search.
https://www.desertsedgerv.com/
https://phoenixmetrorvpark.com/contact/
https://www.comfortcommunities.com/covered-wagon-rv-park-phoenix-az/
So please let me know if I can help with anything else.
Blessings

Call your care coordinator, when I was there gave list of RV park